Cylinders of an engine may be deactivated to reduce engine pumping work and to increase thermal efficiency in cylinders that remain active. A first group of engine cylinders may remain active and combusting air and fuel while a second group of engine cylinders are deactivated by holding intake and exhaust valves closed during an entire cycle of the engine. The first group of engine cylinders is always the same group of cylinders.
More recently, engines have been implemented with deactivating valve operators such that all of an engine's cylinders may be selectively activated and deactivated. This allows the active cylinders that combust air and fuel to periodically deactivate and deactivated cylinders to activate. The combination of active and deactivated cylinders provides the desired engine torque. Further, to provide the desired engine torque, an actual total number of active cylinders may remain the same while the active cylinders that form the actual total number of active cylinders may change from engine cycle to engine cycle. This may be referred to as a rolling variable displacement engine. Such engines provide flexibility to activate different engine cylinders, but the ability to activate and deactivate every engine cylinder adds cost to the engine system, and the cost may be prohibitive for engines with a greater number of cylinders (e.g., six and eight cylinder engines).
The inventors herein have recognized the above-mentioned disadvantages and have developed vehicle systems, comprising: a first vehicle including a first cylinder block and a first cylinder head casting, a first actual total number of deactivating valve operators coupled to the first cylinder head casting; and a second vehicle including a second cylinder block and a second cylinder head casting, a second actual total number of deactivating valve operators coupled to the second cylinder head casting, the first cylinder block same as the second cylinder block, the first cylinder head casting same as the second cylinder head casting.
By configuring different vehicles with the same engine block and cylinder heads and different actual total numbers of deactivating valve operators, it may be possible to reduce vehicle system costs for different vehicles. In particular, a larger higher mass vehicle may be configured with fewer deactivating valve operators than a lower mass vehicle that includes a same engine block and cylinder head as the higher mass vehicle. A smaller actual total number of deactivating valve operators in the higher mass vehicle increases the actual total number of non-deactivating valve operators in the higher mass vehicle so that the higher mass vehicle always has a greater total number of cylinders that cannot be deactivated when the higher mass vehicle's engine is operating as compared to the actual total number of cylinders that cannot be deactivated in the lower mass vehicle. Configuring the actual total number of deactivating valve operators based on vehicle mass or performance objectives may be desirable since the higher mass vehicle uses a greater number of active cylinders to propel the vehicle even at light driver demand conditions. In this way, a same engine block and cylinder head may be configured to reduce system cost and improve engine fuel efficiency.
The present description may provide several advantages. For example, the approach may reduce vehicle system cost. Further, the approach may provide the benefits of cylinder deactivation such as lower engine pumping work. Further still, the approach may improve reliability of cylinder deactivation since fewer deactivating valve operators may be applied based on vehicle configuration and objectives.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.